A major problem in the United States and in other developed countries today is metabolic imbalance, that is, excessive energy intake (eating) versus energy used (work and exercise). Billions of dollars are spent every year in trying to correct the situation, and for paying medical costs that result from the imbalance. Currently, while most of the imbalance appears to accrue from simple overindulgence, the question of relative efficiency remains unanswered. For example, questions as to why some individuals become fat on normal diets. A major cause why these and many other fundamental questions go unanswered is the lack of an appropriate means for studying the problems.
Records kept by the individuals as to their activities and food intake over periods of time are notoriously unreliable, and this has even given rise to the creation of elaborate expensive laboratories to make objective studies of the activities of relatively few individuals under artificial conditions.
U.S Pat. No. 4,830,021, which issued May 16, 1989; and application Ser. No. 554,549, filed Jul. 19, 1990, and which issued Jan. 14, 1992, as U.S. Pat. No. 5,080,105; Ser. No. 554,421, filed Jul. 19, 1990 and which issued Aug. 6, 1991, as U.S. Pat. No. 5,036,856; and Ser. No. 555,307, filed July 20, 1990 and which issued Feb. 19, 1991, as U.S. Pat. No. 4,993,421, all in the name of the present inventor, are directed to monitoring systems in which various physical activities of a subject are monitored along with indications of the emotional state of the subject, and by which certain ambient conditions are also monitored, to determine what effect if any, the physical activities and the emotional state of the subject have on abnormalities in the subject's EKG. Application Ser. No. 556,305, filed Jul. 23, 1990, now abandoned in the name of the present inventor provides a system for monitoring and quantitating musculoskeletal activity of a subject for use in orthopedic and other studies.
By modifications and by adding features to the various monitoring systems disclosed and claimed in the aforesaid patents, the ambulatory metabolic monitoring system of the present invention provides a new and unique capacity for recording energy expenditure and estimating energy intake for both investigation and practical treatment of these problems.
In a majority of individuals, locomotor activity consumes the largest amount of energy. Estimates of such energy consumption due to locomotor activity may be approximated from step rate alone, as described in Co-pending application Ser. No. 07/697,341, which was filed May 9, 1991, in the name of the present inventor as a continuation-in-part of the above-mentioned application Ser. No. 556,305 and which issued Jun. 30, 1992, as U.S. Pat. No. 5,125,412. Since only a characteristic signature in the 1-3 Hz range is required to count step rate, a single inexpensive accelerometer may be used. In addition, by adding foot ground force derivations, as also described in co-pending application Ser. No. 07/697,341, greater accuracy on energy expenditure may be obtained. Accuracy may be further refined by factoring in the heart rate of the individual. Other activities consume correspondingly less energy, for example, standing with occasional steps, standing quietly, seated activity, sitting, lying, lying asleep, and so on. The weight, sex and age of the patient should also be considered.
Estimation of the energy intake of the individual requires additional devices. One such device may be an ordinary digital diary which includes a push-button menu by which the individual may enter the types and quantities of food consumed. A second device is a sensor mounted on the subject which records chewing and swallowing activities, from which an estimation of intake may be derived, and which may be used to verify and augment the manually entered data.
Data from the sensors and devices referred to above may be processed to arrive at an estimation of the energy intake of a individual versus the energy consumed during the period.
Several monitoring systems will be described herein to fit varying needs of the operator. These needs may range, for example, from the researcher who requires as much information as possible, to the clinician who merely requires concise summaries regarding diet and exercise, and other specialists who require certain details for counseling and discussions with patients.